Many different car wash systems have been designed to eliminate the need to hand wash a vehicle. These systems vary greatly in operation and complexity. Simple systems provide an owner with a convenient, hand-operated system. Typically, these hand-operated systems are located in garage like stalls and adapted to wash stationary vehicles. More complex systems provide for relative motion between the vehicle and the washing apparatus and eliminate owner participation. These complex systems are typically configured as either "roll-over" (i.e. in-bay) or "tunnel" systems. In roll-over systems, the vehicle remains stationary and the wash apparatus moves on a path about the vehicle. In tunnel systems, the apparatus remains stationary and the vehicle moves along a path through the apparatus.
Car wash systems also vary in cleaning methods employed. One type of car wash system uses a scrubbing system in combination with soap and rinse spray devices. Typically, the scrubbing system includes a plurality of mitter curtains adapted to engage the vehicle. The mitter curtains attach to an overhead support and have scrubbing strips which hang freely into the vehicle path. The overhead support generally moves to impart a swinging or flapping motion to the freely hanging scrubbing strips. In this manner, the mitter curtains physically wipe, or scrub, dirt from the vehicle during the wash cycle.
In general, mitter curtain systems provide an effective wash system due to the direct contact of the scrubbing strips with the vehicle surface. However, movement of the overhead structure inherently imparts the most scrubbing motion to the extreme free end of each mitter curtain, so that the vehicle areas contacted by these free ends receive the maximum cleaning action. Since mitter curtains need to be of a sufficient length to contact the lower vehicle surfaces, such as the bumpers and running boards, the free ends of the mitter curtains contacting these lower vehicle surfaces generate the greatest scrubbing motion, whereas the higher portions of the mitter curtains, which contact the higher portions of the vehicle surfaces such as the roof, generate less associated scrubbing motion. These higher vehicle portions, therefore, receive a lower degree of cleaning action resulting in the washing action varying with respect to the different surfaces of the vehicle.
Additionally, contact-type systems have the potential to damage the surface of the vehicle. Abrasive dirt particles can be trapped on the mitter curtains and noticeably scratch the painted surface of the vehicle. This is particularly likely after subjecting a vehicle to repeated washes in the contact-type apparatus.
In order to avoid the potential damage associated with contacting the vehicle surface, another type of wash system utilizes only soap and water spray. In the most basic non-contact system, a hand held wand is physically manipulated by a vehicle owner to direct soap and high pressure spray onto the vehicle surface. In more elaborate systems, nozzles are attached to a framework which moves relative the vehicle, and the spray is directed through the nozzles onto the vehicle surfaces. In either form, the vehicle is cleaned solely by the action of the soap and high pressure water spray directed onto the vehicle surfaces.
Non-contact systems avoid the potential for damage to the vehicle inherent in contact systems, but they typically do not clean a vehicle as effectively as a contact system. Vehicle owners generally have a preference for a particular type of car wash system depending on the result desired. Specifically, vehicle owners desiring the least potential for surface damage typically prefer the non-contact, spray systems, accepting a less effective wash, and vehicle owners desiring the most effective wash, regardless of the potential for surface damage, typically prefer the contact systems.